The invention relates to a wastewater lifting station having at least one bulky-material collection container having at least one separating screen which is arranged in the interior thereof for wastewater which is to be guided therethrough and is loaded with bulky materials, wherein the separating screen subdivides the bulky-material collection container into a bulky-material loaded region and a bulky-material free region, and wherein the separating screen is connected so as to be pivotable via a hinge to a flange of the bulky-material collection container.
This means that the separating screen is pivotably mounted in the interior of the bulky-material collection container. To this end, the separating screen is connected to the flange via the hinge. In this context the hinge in principle may also be configured as an integral hinge or as a hinge which is made available by a flexible strip, respectively. The flange generally defines a fastening region for the hinge on the bulky-material collection container or in the interior thereof.
In a wastewater lifting station of the construction described at the outset according to German patent document no. DE 1 609 166, the procedure is such that the separating screen is configured as a rake having a non-return flap. The rake is covered by the non-return flap. The rake teeth of the rake here do not fully fill the entire cross section of a connection line. As a consequence of the cross section which is kept open with the aid of the rake, the rake is no longer intended to be able to be obstructed by the bulky materials. On account thereof, operational disruptions are to be avoided.
In the further prior art as per International patent document no. WO 2010/025852 A1, a wastewater lifting station in which a connection line having a combined shut-off/screening installation is connected to the bulky-material collection container is described. The shut-off/screening installation is disposed in the interior of the bulky-material collection container. Moreover, the separating screen and the shut-off/screening installation in question are aligned so as to be substantially mutually perpendicular. On account thereof, even large quantities of wastewater having solids located therein may be managed.
The state of the art in principle has been successful in cases where wastewater lifting stations lift to a specific level wastewater which has generally been collected at the end side of a wastewater storage space. Even large quantities of wastewater may be managed here. On account thereof, there is the overall potential for wastewater to be able to be further treated in a remote wastewater treatment plant which is at a higher elevation, for example. By way of the at least one bulky-material collection container a pump which is downstream of the bulky-material collection container will be protected from the solids located in the wastewater. On account thereof, pumps of a comparatively small constructive size with low drive power may be employed for the described object of lifting wastewater.
This is to say that the solids are initially separated from the wastewater or from a conveying medium, respectively, prior to this conveying medium entering the pump. This is substantially ensured by the bulky-material collection container having the separating screen disposed in the interior thereof. It is only the wastewater which is free of bulky-material and is consequently pre-cleaned which in this context is transferred into a fluid collection container which is downstream of the bulky-material collection container. The pre-cleaned wastewater may now be readily processed with the aid of said pump and, in particular, be lifted to the desired level. During this procedure at the same time the solids which before have been retained by the separating screen are released therefrom again.
However, the problem increasingly arises in practice of the solids which have been trapped by the separating screen not, or not completely, being released from the separating screen during flushing out of the separating screen in the course of the wastewater lifting procedure. The root cause thereof is that there is a growing proportion of short and long fibrous material in wastewater today. Moreover, a growing proportion of fats and granules are observed, so that the latter in conjunction with the fibers often clog the separating screens employed. Altogether, this may lead to undesirable stoppage times. The invention proceeds from here.
The invention is based on the technical object of refining a wastewater lifting station of this type such that cleaning of the separating screen by back-flushing, in particular using pre-cleaned wastewater, is performed in a manner which is flawless and as complete as possible.
In order for this object to be achieved the invention, in the case of a wastewater lifting station of the generic type, includes a separating screen at least in the hinge-remote peripheral region has at least one cut-out which is open toward the outside, that is to say toward the peripheral region. It has proven successful, for example, for the hinge-remote peripheral region of the separating screen to be configured in the manner of a comb.
The invention at this point firstly proceeds therefrom that the separating screen subdividing the bulky-material collection container is connected so as to be pivotable to the flange via the hinge in the interior of the bulky-material collection container. In conjunction with the flange, the separating screen which is connected via the hinge to the flange consequently ensures that the bulky-material collection container is subdivided in the described manner into the bulky-material loaded region and the bulky-material free region.
In order for the solids which adhere thereto and, in particular, the fibers or other expansive solids to be flawlessly removed from the separating screen in the course of back-flushing or flushing out of the separating screen, the invention provides that the separating screen at least in the hinge-remote peripheral region has at least one cut-out which is open toward the outside, for example is configured in a comb-type manner in the hinge-remote peripheral region in question. The invention here proceeds from the concept that the hinge-remote peripheral region in question primarily ensures the closure and the subdivision, respectively, of the bulky-material collection container by the separating screen.
The hinge-remote peripheral region most often bears on a sealing region of the bulky-material collection container, in the simplest case on the inner wall thereof. On account of this sealing region now being equipped with the cut-out which is open toward the outside, any fibrous or elongate solids which may potentially adhere to the separating screen will be stripped away, so to speak, from the hinge-remote peripheral region of the separating screen by the stream during back-flushing of the separating screen. As a consequence of the cut-out which is open toward the outside, the fibers may no longer be retained by the separating screen. The separating screen which most often bears on the sealing region of the bulky-material collection container in an oblique manner during the flushing procedure is raised from said sealing region, so that the flushing stream utilizes the slot between the raised separating screen and the sealing region of the bulky-material collection container as a passage. Since the cut-out which is open toward the outside is disposed on the separating screen in the region of the passage, even fibrous solids are readily released from the separating screen during this procedure. As a matter of fact, the cut-out or the pluralities of cut-outs, respectively, is/are indeed opened in the direction of flow of the flushing stream.
It is understood in principle that not only one separating screen but a plurality of successively disposed separating screens, for example, having corresponding cut-outs may be implemented. The separating screens which consequently are successively disposed in the direction of flow here may be designed such that the cut-outs are disposed in a mutually offset manner. However, most often only one separating screen will be operated in order for the costs to be minimized and for contamination to be avoided. This is where the substantial advantages are to be seen.
It has proven successful for the separating screen in the hinge-remote peripheral region to be equipped with a plurality of longitudinal slots between comb-type webs. The hinge-remote peripheral region here typically defines the peripheral region of the separating screen which is opposite the hinge for the pivotable connection of the separating screen to the flange. Since the hinge is most often connected to the flange in the interior of the bulky-material collection container at the top side of the separating screen, the hinge-remote peripheral region of the separating screen corresponds to the base region thereof which, in the course of the intake of wastewater loaded with bulky material, bears on the sealing region of the bulky-material collection container or on the inner wall thereof, respectively.
The individual longitudinal slots between the comb-type webs in the hinge-remote peripheral region of the separating screen as per an advantageous design embodiment are all configured so as to be open toward the outside. On account thereof, solids of a specific size are retained, on the one hand, namely such which in terms of their diameter cannot pass through the longitudinal slots. At the same time, the opening of the longitudinal slots toward the outside in the hinge-remote peripheral region ensures, on the other hand, that any potential fibers or elongate bulky materials during flushing of the separating screen are stripped away, by the stream flowing in the same direction, from the separating screen which then is at least slightly opened and raised from the sealing region on the bulky-material collection container.
The comb-type webs are generally disposed so as to be mutually equidistant, that is to say equally spaced apart. The reason therefor is to provide in each case identical screening conditions for the bulky materials to be retained. Moreover, it has proven successful for the longitudinal slots and the webs to run so as to be approximately mutually parallel. In principle it is also possible for the longitudinal slots and the webs to be mutually aligned radially. It is ensured overall in this way that solids of a specific size are flawlessly retained by the separating screen.
The bulky-material collection container is most often hollow-cylindrical. Since the separating screen, specifically in conjunction with the flange, subdivides the hollow-cylindrical bulky-material collection container into the bulky-material loaded region and the bulky-material free region, it is recommended that the separating screen is configured in the manner of a circular-disk segment up to being an elliptical segment. This applies to the flange in a comparable way. This means that the circular-disk segment type flange and the separating screen, which is likewise circular-disk segment type to elliptical segment type, when viewed from the front collectively and typically define a circular disk which is adapted to or may be adapted to the diameter and the layout of the hollow-cylindrical bulky-material collection container.
Besides the separating screen, a shut-off installation is usually connected to the flange. This shut-off installation in conjunction with the separating screen may assume a screening function. Then the shut-off installation is a combined shut-off/screening installation, such as is described in detail in International patent document no. WO 2010/025852 A1. However, this is not mandatory.
It has proven successful for the separating screen to be connected via the hinge to the flange at an inclination angle in relation to the sealing region or to the inner wall of the bulky-material collection container, respectively. This is to say that the separating screen in the installed and non-pressurized state (installed state) while considering the inclination angle in question bears on the sealing region in the interior of the bulky-material collection container. Conversely, the separating screen during the back-flushing procedure and any pressurizing associated therewith is raised from the sealing region. The inclination angle is reduced thereby.
A bypass is most often additionally provided. For reasons of particularly compact and cost-effective manufacturing it has proven successful in this context for the bypass to be provided in the bulky-material free region of the bulky-material collection container. To this end a flow baffle plate of corresponding design may be operated as a bypass. It goes without saying that this is not mandatory, since operation is just as readily possible using a bypass which is disposed outside the bulky-material collection container, or entirely without a bypass.
Finally, it has proven successful for the flange supporting the separating screen, the separating screen, optionally the shut-off installation, and the optional bypass to form a functional unit which is insertable into the bulky-material collection container. In principle, the flange may also be a terminal flange of the respective bulky-material collection container, or be connected to one of the latter, so that the functional unit in principle needs only to be completed using a further terminal flange (to the bulky-material collection container). On account thereof, any potential maintenance work may be carried out in a particularly simple manner, and the separating screen may be readily replaced if and when required.
As a result, a wastewater lifting station which even captures long and fibrous or generally elongate bulky materials and is not prone to clogging is provided. During flushing out of the wastewater lifting station according to the invention the separating screen is initially raised from its bearing on the sealing region in the interior of the bulky-material collection container, on the one hand. On account thereof, a defined passage between the hinge-remote peripheral region of the separating screen and the sealing region in question on the sleeve or on the inner wall of the bulky-material collection container for the pre-cleaned wastewater streaming therethrough is established, on the other hand. Additionally, the separating screen according to the invention in the hinge-remote peripheral region is equipped with at least one cut-out which is open toward the outside, so that the described flushing procedures ensure that any potential fibers or generally elongate solids are stripped away from the separating screen by the stream. On account thereof and as opposed to the prior art, in particular long and fibrous bulky materials cannot or can no longer clog the separating screen according to the invention, and long service life without repairs or maintenance works is to be expected. The substantial advantages are to be seen herein.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.